The present invention relates generally to four-wheel drive vehicles and, more particularly, to a part-time transfer case for use in front wheel drive vehicular applications.
With the advent of increased consumer popularity in four-wheel drive passenger cars and sport/utility vehicles, part-time transfer cases are more frequently being incorporated in vehicular driveline applications. As is known, conventional part-time transfer cases are used in four-wheel drive vehicles to normally deliver power to the rear wheels of the vehicle for establishing a two-wheel drive operating mode. However, such part-time transfer cases are also operable for selectively delivering power to both the front and rear wheels for establishing a four-wheel drive operating mode. Since the weight distribution for most four-wheel drive vehicles is biased toward the front wheels (i.e., due to the weight of the engine and transmission), during two-wheel drive operation the greatest potential for wheel slip due to lost traction is associated with the driven rear wheels. This being the case, the need exists to provide a part-time transfer case which normally delivers power to the front wheels of the vehicle in the two-wheel drive mode and yet is operable for selectively delivering power to both the front and rear wheels in the four-wheel drive mode.